Onycholyda flavicostalis Shinohara, 2012

Shinohara, Akihiko, Kiyoshi, Takuya, Wei, Meicai & Kameda, Yuichi, 2018, Identification of Larvae and Recognition of New Synonymy for Two Chinese Onycholyda Sawflies (Insecta: Hymenoptera: Pamphiliidae) based on Molecular Data, Species Diversity 23 (1), pp. 75-81 : 77-80

Onycholyda flavicostalis Shinohara, 2012 ( Fig. 2 )

Onycholyda flavicostalis Shinohara, in Shinohara and Wei, 2012: 57 .

Distribution. China (Shaanxi, Hubei, Hunan, Sichuan).

Host plants. Rubus adenophorus Rolfe. , Rubus sp.

Field observations and rearing records. Case A. One leaf-roll on Rubus adenophorus containing seven gregarious middle-instar larvae was found in Mt. Yunshan, Hunan Province on May 2, 2009 . The leaf-roll was on the underside of the leaf and remains of the egg shell were not found. The larvae were fixed on May 8 (including sample nos. 783–785, Table 1). Case B. Nine leaf-rolls, one each containing one larva, were found on R. adenophorus at Yaolangou, Muyu, Shennongjia , Hubei Province, on May 18, 2010. All the nine larvae were fixed in ethanol on May 19 and 21 (one of them, sample no. 466). Another leaf-roll containing three larvae was also found on R. adenophorus at the same locality on the same day. The three larvae were fixed in ethanol on May 22 (sample nos. 470–472). For all the ten leaf-rolls examined, remains of the egg shells were not found. Case C. Two leaf-rolls were found on R. adenophorus in Qianjiaping, Shennongjia , Hubei Province on May 18, 2012. One of them ( Fig. 2A ) contained one larva and the other ( Fig. 2B ) contained two larvae. Each of the leaf-rolls was on the underside of the leaf and remains of the egg shell were not found. The larvae matured (one of them in Fig. 2C ) and were fixed on May 22 (including sample nos. 775, 777). Case D. Two groups of eggs, consisting of five eggs and three eggs, respectively, were found on the same leaf of R. adenophorus in Guanmenshan, Shennongjia , Hubei Province on May 23, 2012. The groups of eggs were deposited on the lateral veins in a line in the basal part of the underside of a leaf ( Fig. 2E, F ). The eggs hatched on May 27 and the larvae were fixed on June 6 (one of them sample no. 781). Case E. One leaf-roll containing one larva was found on Rubus sp. along a narrow unpaved car road at about 1600 m in altitude about 32 km from Baoguosi on Mt . Emeishan, Sichuan Province, on May 14, 2015 . The larva was fixed in ethanol on May 18 (sample no. 587).

Egg. Normal for pamphiliids, yellowish white, deposited in a row along lateral veins in basal part of the leaf ( Fig. 2E, F ).

Larva. Mature larva ( Fig. 2C, D ). Head black, with epicranial suture and part of clypeus greenish; antenna creamy white, each antennomere more or less dark brownish; labrum and mandible dark brown, palpi pale brown, and other mouthparts greenish, partly marked with blackish brown; trunk pale greenish, terminal segment largely creamy white; cervical sclerite partly blackish; thoracic legs and subanal appendage greenish white; suranal hook dark brown.

Remarks. Our molecular analysis has clearly shown that the larvae feeding on Rubus adenophorus from Shennongjia, Hubei Province, and Mt. Yunshan, Hunan Province, and those feeding on Rubus sp. from Mt. Emeishan, Sichuan Province, belong to O. flavicostalis , which was described from Mt. Yunshan, Hunan Province. This is the first record of the host plant and larva of O. flavicostalis and the first distribution record of this sawfly from Hubei and Sichuan Provinces.

Onycholyda flavicostalis and O. odaesana Shinohara and Byun, 1993 , occur together on Mt. Yunshan in Hunan Province ( Shinohara and Wei 2012) and the larvae of the two species feed on the same host plant, R. adenophorus ( Shinohara and Wei 2010; present study). The larva of O. flavicostalis is a gregarious or solitary leaf-roller with a black head, whereas the larva of O. odaesana is solitary and has a pale brown head with three black spots. Among the non-Chinese species, the larva of O. esakii (Takeuchi, 1938) from Japan is a gregarious leaf-roller and has a color pattern very similar to that of O. flavicostalis ( Shinohara and Kojima 2009) . We are not able to distinguish the larvae of the two species based on a current knowledge besides the differences in distribution and the host plant species. The mature larva of O. sichuanica also has an entirely black head and a pale green trunk but the cervical sclerite is entirely pale in this species, unlike those of O. flavicostalis and O. esakii .

As noted in the section of field observations above, the female of O. flavicostalis deposits eggs in a row (up to seven eggs together) and the middle-instar larvae live gregariously in one leaf-roll, whereas the late-instar larvae may live in a small group or even solitarily. The range of variation in the larval gregariousness of this species should be confirmed by obtaining further information.

Figures

Fig. 2. Onycholyda flavicostalis, larval leaf-rolls (A, B), mature larva (C, D), and eggs deposited on the leaf of Rubus adenophorus (E, F), all collected at Shennongjia, Hubei Province, and photographed at the site (A, B, E, F) or indoors (C, D) by A. Shinohara. —A, Leaf-roll (one larva, sample no. 775 inside), Qianjiaping, May 18, 2012; B, leaf-roll (two larvae, including sample no. 777 inside), Qianjiaping, May 18, 2012; C, mature larva (sample no. 775), May 22, 2012; D, mature larva (sample no. 781 from one of the eggs shown in E), June 6, 2012; E, leaves with two groups of eggs (arrowed), Guanmenshan, May 23, 2012; F, same, enlarged.